Latching solenoid

ABSTRACT

A latching type magnetically operated solenoid is provided for controlling a valve, or other instrumentality, which does not require continuous current flow through the energizing coils to hold the solenoid in either of its two operating positions. The solenoid includes two coils and associated independent magnetic circuits. When one coil is pulsed, the solenoid armature is moved to a first position, and when the second coil is pulsed the solenoid armature is moved to a second position. A mechanical toggle assembly is coupled to the armature of the solenoid to hold the solenoid in either of its two positions, until it is pulsed to its other position.

D United States Patent 1 on 3,895,331 Saarem July 15, 1975 i 1 LATCHING SOLENOID Prt'mar ExuminerG. Harris t M l .s ,c t N Y [75] or yr arson y ev Attorney, Agent, or Firm.lessup & Beecher [73] Assignee: Richdel, Ina, Carson City, Nev.

[22] FilCdZ May 20, 1974 57 ABSTRACT App! 471319 A latching type magnetically operated solenoid is provided for controlling a valve, or other instrumentality, [52] US. Cl 335/253; 335/171 which does not require Continuous current flow 51 int. Cl. non 7/08 through the energizing coils to hold the Solenoid in 5 Field f S h H 335/1 7 1 3 170 71 ther of its two operating positionsv The solenoid in- 335/253 254 2 3 eludes two coils and associated independent magnetic circuits. When one coil is pulsed, the solenoid anna- 5 References Ci d ture is moved to a first position, and when the second UNITED STATES PATENTS coil is pulsed the solenoid armature is moved to a second position. A mechanical toggle assembly is coupled eefe 55 53; to the armature of the solenoid to hold the solenoid in 24O5'396 8/1946 Z Z "3"35/262 x either of its two positions, until it is pulsed to its other 2.853.658 9/1958 Lindenberg.... 335/254 Posltlon- 3,235,777 2/1966 Hatashila 335/254 9 Cl 2 D F, 3,743,898 7/1973 Sturman it 335/254 x l6 32) f (32 f k j 424 w42 LATCHING SOLENOID BACKGROUND OF THE INVENTION The solenoid of the invention finds particular. although not exclusive. utility in conjunction with valves for automatic sprinkler systems. When so used. the solenoid may be automatically controlled to turn the valves on or off for prolonged periods of time. and without the need for continuous current flow in the solenoid when the valves are either on or off.

Latching solenoids in general are known. However. the prior art latching solenoids. for the most part. are complex and expensive. The latching relay of the invention, on the other hand, is reliable, simple and rug ged in its construction. and it may be readily adapted for outdoor and underground use. The latching solenoid of the invention involves a relatively few parts. and it is relatively inexpensive to fabricate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation showing a solenoid valve which is constructed to incorporate a latching solenoid constructed in accordance with one embodiment of the invention; and

FIG. 2 is a sectional view of the valve. on a somewhat enlarged scale with respect to the representation of FIG. I, and taken essentially along the line 2-2 of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The solenoid actuated valve assembly illustrated in FIGS. 1 and 2 includes. for example. a central magnetic core section which is positioned coaxially with the longitudinal central axis of the valve assembly. The magnetic core section 10 may. for example. be in the form of an elongated circular rod composed. for example, of 430E Series stainless steel.

The magnetic core 10 is inserted into a metallic sleeve 14 which may be composed of non-magnetic metal, such as 304 Series stainless steel. A second magnetic core section I2 is also supported within the sleeve 14 in coaxial relationship with the core section 10, and axially spaced therefrom. The core section 12 has a tubular configuration. and it too may be composed, for example. of 430F Series stainless steel. The cores l0 and 12 may be attached to the sleeve 14 by a suitable adhesive, such as an epoxy resin altermately. the core 12 may be unattached to the sleeve 14 for ease of removal of the armature assembly for cleaning or resplacement purposes.

A first annular member 16 formed of magnetizable material. for example. of cold rolled steel, is fitted over the end of the core section 10, and it surrounds the core section in a coaxial relationship therewith. A second annular member 18 is mounted in like manner on sleeve I4 to surround a magnetic core section 20, and a further annular magnetizable member 22 is mounted on the sleeve in spaced relationship with the annular member I8 to surround a magnetic core section 24. The annular members I8 and 22 are separated by a non'magnetic annular member 26, which is mounted on the sleeve 14 between the annular members 18 and 22, and which serves to isolate the magnetic paths through the two annular members. The member 26, for example, may be formed of appropriate plastic material.

The magnetic core sections and 24 also have a tubular configuration. and are mounted on an elongated armature or plunger which is movable axially along the central axis of the assembly. The core sections 20 and 24 likewise may be composed of 430E Series stainless steel. or other appropriate magnetic material. The armature is non-magnetic.

A first bobbin 32 formed. for example, of molded epoxy resin is mounted on the end of sleeve 14 between the annular members 16 and IS in bridging relationship with the core sections l0 and 20. A second bobbin 34 is mounted on the sleeve 14 between the annular member 22 and a further annular member 36, and in bridg ing relationship with the core sections 12 and 24. The annular member 36 may also be formed of appropriate magnetizable materials such as cold rolled steel. and it surrounds the first magnetic core section I2 in coaxial relationship therewith.

A first electric energizing coil 40 is wound on the bobbin 34. and second electric energizing coil 42 is wound on the bobbin 32. The coil 40 is energized through a lead 44 (FIG. I] and a common lead 46. whereas the coil 42 is energized through a lead 48 and the common lead 46. The coils 40, 42 may be wound so that more force is created for one direction of motion of the armature as opposed to the other. This would allow a fail safe design in the case of using a battery as a power source. Then should there be just enough power in a nearly discharged battery to move the armature in one direction. there would always be enought power to return it to the initial position. In the case of a sprinkler valve. the control could be such that the valve would fail to open before it would fail to close thus providing the fail safe feature.

A cup-shaped outer shell or casing 50, formed of appropriate magnetizable material. such as. for example. cold rolled steel. is fitted over the annular members I6, 18 and 22 in coaxial relationship with the core sections. The sleeve 14 extends through an aperture in the closed end of the shell 50, a shown in FIG. 2. The central opening in the end of the shell 50 through which the sleeve 14 extends may be pierced in the shell by a suitable piercing tool, with the metal forming an axially extending skirt section 50a of the shell extending tightly around the end of the sleeve 14 to increase the surface contact between the shell and the sleeve for enhanced magnetic properties of the assembly.

A plastic collar 52 is positioned against the end of the sleeve 50 to surround the end position of the assembly, and to provide an appropriate mounting means therefor. For that purpose. the collar 52 may be threaded as shown. The core section I2 protrudes axially beyond the casing 50 and sleeve 14, and it has a counter bored end section 12a. An O-ring 56 is provided between the flared end of the sleeve [4 and the interior ofthe collar 52 for sealing purposes, when the solenoid is used in conjunction with a valve. In construction. the O ring is first fitted over the sleeve 14, and the sleeve is then flared to set all the components of the coil assembly in their assembled positions.

The armature 30 may be formed of any appropriate non-magnetic material. The end of the armature may be configured to receive a rubber member 58 which operates in conjunction with an appropriate valve seat when the solenoid is used to open and close the valve.

The armature 30 moves axially in the assembly between a first and a second limiting position. The arma ture is firmly held in either of the two limiting positions by means of one or more toggle assemblies. such as the assembly 60 shown in FIG. 2. The toggle assembly 60 includes a toggle member 62 which is spring biased by a spring 64. and which acts in an over-center manner so that the toggle member 62 is biased by the spring 64 either to one side or to the other of the central axis of the toggle assembly. so that the armature 30 may be firmly held in either of its two limiting positions.

In the operation of the assembly. when the coil 40 is pulsed, for example. the resulting magnetic flux set up in the magnetic field including the annular members 22 and 36, the shell 50. and the core sections 12 and 24. causes the core section 24 on the armature to be attracted to the stationary core section 12. so as to move the armature 30 to its first limiting position. The armature is held in its first limiting position by the toggle action of the toggle assembly 60. even though the electric current is discontinued in the coil 40.

The armature 30 is held in its first limiting position until the coil 42 is pulsed with an electric current. This latter action causes the stationary core section 10 to attract the armature core section 20. The resulting mag netic flux extends through a magnetic path including the shell 50 and the annular members [6 and 18. so that the toggle assembly 60 snaps to its other position to hold the armature in its second limiting position until the coil is again pulsed.

The invention provides. therefore. a simple and rugged solenoid assembly in which two independent paths are used. in conjunction with a mechanical toggle assembly. to move the armature to one limiting position or the other. with the armature being retained by the toggle assembly in either of the two limiting positions. until the solenoid is again pulsed. When the solenoid is mounted in valve housing. or equivalent socket. the housing traps the tubular core section 12 and associated armature components in the illustrated position. In a constructed embodiment the parts 20, 24, 30, I2. 62. 60 and 64 of the valve assembly are removable. leaving only the coil sub-assembly held in assembled condition by the flare at the end of sleeve 14.

It will be appreciated that the illustrated embodiment may be modified without departing from the concept of the invention. For example. the toggle assembly may take a variety of forms. including over-center spring washers. and other known over-center devices.

Therefore. while a particular embodiment of the invention has been shown and described. modifications may be made. It is intended in the claims to cover the modifications which come within the spirit and scope of the invention.

What is claimed is:

l. A solenoid assembly including: a first elongated central core section formed of magnetizable material positioned on the central longitudinal axis of the assembly; a second elongated central core section of tubular configuration coaxial with said first core section and axially spaced therefrom; an elongated central axially movable armature coaxial with said first core section; a third elongated core section of tubular configuration coaxially mounted on said armature between said first and second core sections and in axially displaced rela tionship with said second core section; a fourth elongated core section of tubular configuration coaxially mounted on said armature between said first and third core sections and in axially displaced relationship with said first core section; a pair of axially spaced electrical energizing coils mounted in coaxial relationship with said core sections. said first coil surrounding and bridg ing said first and fourth core sections. and said second coil surrounding and bridging said second and third core sections; mounting means for said first and second core sections and for said first and second coils. said armature being movable in said mounting means along said central longitudinal axis; and means including mechanical toggle means intereoupling said armature to said mounting means. so that an electrical pulse energizing the first coil causes the armature to move along the central longitudinal axis to a first position. and an electrical pulse energizing the second coil causes the armature to move along the central longitudinal axis to a second position.

2. The solenoid assembly defined in claim 1, in which said mounting means includes a sleeve mounted coaxially with said armature and surrounding said core sections. and in which said first and second coils are mounted on said sleeve.

3. The solenoid assembly defined in claim 2, in which said mounting means further includes a shell of magnetizable material mounted coaxially with said sleeve and said first and second coils in surrounding relationship therewith and having an end wall through which said sleeve extends.

4. The solenoid assembly defined in claim I, in which said mechanical toggle means includes at least one radially extending over-center spring-loaded toggle memher.

5. The solenoid assembly defined in claim 3., and which includes a plurality of annular members of magnetizable material mounted coaxially with said core sections. said annular members being spaced axially along the central longitudinal axis, and interposed respectively between the first and second coils. and respectively between the coils and the end of said shell.

6. The solenoid assembly defined in claim 5, in which a pair of said annular members are interposed between the first and second coils. and which includes a further annular member of non-magnetic material mounted coaxially with said core sections and interposed between said pair of annular members.

7. The solenoid assembly defined in claim 1, in which the energy of the electrical pulse energizing the first coil to cause the armature to move to the first position is greater than the energy of the electrical pulse energizing the second coil to cause the armature to move to the second position.

8. A solenoid assembly including: a casing; tubular magnetic core means mounted in said casing; an elongated armature mounted in said casing coaxial with said magnetic core means and axially movable in the casing along the longitudinal axis thereof; a pair of electrical energizing coils mounted in said casing in co axial relationship with said core means and coaxially spaced along the longitudinal axis of the casing; and mechanical toggle means including at least one radially extending over-center spring-loaded member intercoupling the armature to the casing means. so that an electrical pulse energizing said first coil causes the armature to move along the longitudinal axis of the casing to a first axial latched position. and an electrical pulse energizing the second coil causes the armature to move along the longitudinal axis of the casing to a second axial latched position.

9. The solenoid assembly defined in claim 8. and which includes two of said mechanical toggle means diametrically positioned with respect to one another. 

1. A solenoid assembly including: a first elongated central core section formed of magnetizable material positioned on the central longitudinal axis of the assembly; a second elongated central core section of tubular configuration coaxial with said first core section and axially spaced therefrom; an elongated central axially movable armature coaxial with said first core section; a third elongated core section of tubular configuration coaxially mounted on said armature between said first and second core sections and in axially displaced relationship with said second core section; a fourth elongated core section of tubular configuration coaxially mounted on said armature between said first and third core sections and in axially displaced relationship with said first core section; a pair of axially spaced electrical energizing coils mounted in coaxial relationship with said core sections, said first coil surrounding and bridging said first and fourth core sections, and said second coil surrounding and bridging said second and third core sections; mounting means for said first and second core sections and for said first and second coils, said armature being movable in said mounting means along said central longitudinal axis; and means including mechanical toggle means intercoupling said armature to said mounting means, so that an electrical pulse energizing thE first coil causes the armature to move along the central longitudinal axis to a first position, and an electrical pulse energizing the second coil causes the armature to move along the central longitudinal axis to a second position.
 2. The solenoid assembly defined in claim 1, in which said mounting means includes a sleeve mounted coaxially with said armature and surrounding said core sections, and in which said first and second coils are mounted on said sleeve.
 3. The solenoid assembly defined in claim 2, in which said mounting means further includes a shell of magnetizable material mounted coaxially with said sleeve and said first and second coils in surrounding relationship therewith and having an end wall through which said sleeve extends.
 4. The solenoid assembly defined in claim 1, in which said mechanical toggle means includes at least one radially extending over-center spring-loaded toggle member.
 5. The solenoid assembly defined in claim 3, and which includes a plurality of annular members of magnetizable material mounted coaxially with said core sections, said annular members being spaced axially along the central longitudinal axis, and interposed respectively between the first and second coils, and respectively between the coils and the end of said shell.
 6. The solenoid assembly defined in claim 5, in which a pair of said annular members are interposed between the first and second coils, and which includes a further annular member of non-magnetic material mounted coaxially with said core sections and interposed between said pair of annular members.
 7. The solenoid assembly defined in claim 1, in which the energy of the electrical pulse energizing the first coil to cause the armature to move to the first position is greater than the energy of the electrical pulse energizing the second coil to cause the armature to move to the second position.
 8. A solenoid assembly including: a casing; tubular magnetic core means mounted in said casing; an elongated armature mounted in said casing coaxial with said magnetic core means and axially movable in the casing along the longitudinal axis thereof; a pair of electrical energizing coils mounted in said casing in co-axial relationship with said core means and coaxially spaced along the longitudinal axis of the casing; and mechanical toggle means including at least one radially extending over-center spring-loaded member intercoupling the armature to the casing means, so that an electrical pulse energizing said first coil causes the armature to move along the longitudinal axis of the casing to a first axial latched position, and an electrical pulse energizing the second coil causes the armature to move along the longitudinal axis of the casing to a second axial latched position.
 9. The solenoid assembly defined in claim 8, and which includes two of said mechanical toggle means diametrically positioned with respect to one another. 